No. It's not always and here's why.
Firstly, the clever thing about the site is that it gets you to craft the items that give the smallest loss while preparing to craft items in the next tier. So, in Tier 1 of each rank you convert raw mats to processed mats and components. Makes sense, right? No, not always.
I am currently using the site to level Huntsman. To get me from 225 to 300 it had me set to do the crafts in Figure 1. Now, what you can't see here is that, today, Hard Longbow Staves sell at a decent profit. As do Darksteel Rifle Barrels. Most of the other things that it asks you to make are a net loss. You can use gw2spidy to check these things, for example. To level from 225 to 250 in the cheapest way possible you should probably just convert logs to planks, make longbow staves and sell them at a profit. Yes, that does mean you won't have any components to craft in Tier 2 but it might be cheaper to buy them straight from the TP anyway! It is today and that's the thing about GW2 it pays to research.
|Figure 1 - Huntsman 225 - 300|
What that means, again, is that the components you crafted in Tier 1 might not make the most profitable Rare weapons. So what the guide recommends for Tier 1 may not even be useful if you decide to craft Rares instead.
Thirdly, in my case, levelling Huntsman, you would never know from gw2crafts that you can make unique Rare weapons at level 250 using a Sun Beads. If you make 6 of these weapons you'll be at 275 and they sell for a profit.
For my final push to 300 the guide recommends making 8 Sigils. These will cost me 34.46s a pop to craft. However, looking at gw2spidy again, I can see at least 7 recipes I can make that will yield a profit instead of a 2.59g loss.
Like I said, it's a great site and a pretty convenient way to level a craft but even the "slow" guides could lose you a small fortune and if money is tight it's a mistake you can ill afford to make.